Method of treating molding-sand.



PATBNTVED MAR. 17, 1903.

APPLIOATION FILED OUT. 14, 1902.

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PATENTED MAR. 17, 1903.

W. J. PATTERSON. METHOD OF TREATING MOLDING SAND.

APPLICATION FILED OUT. 14, 1902.

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a e a a e m w No. 722,885. PATENTBD MAR. 17,- 1903.

' W. J. PATTERSON.

METHOD OF TREATING MOLDING SAND.

APPLICATION FILED 00114, 1902.

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UNITED STATES,

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WILLIAM J. PATTERSON, OF PITTSBURG, PENNSYLVANIA.

METHOD OF TREATING MOLDING-SAND.

SPECIFICATION formingpart of Letters I? atentNo..722,885, dated March 17, 1903. Application filecloctober 14 i962. a ria No. 127,311. (No model.)

To all'whom it may concern:

Be it known that 1, WILLIAM J. PATTER- SON, a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in.

ing a smoother surface than is ordinarily the case.

In all foundry plants the sandused in making the sand molds is used over and over again, the practice being that after the castings are removed from the I molds on the dumping-floor to temper the sand-with water until it is of the proper consistency, screen the same, and again return it to the moldingroom. It has been found that under certain conditions sand which has once been used in a mold after being treated in this way is full of small globules or kernels, which produce a roughness of the mold-face, so that-the casting likewise receives a rough surface. These small globules or kernels are formed by a number of grains of sand adhering together, but from what cause, whether due to the heat of the molten metal in the prior casting or whether due to the action of the water in temporing the sand,is not definitely known. Their existence, however, is well known, and the injurious effect they produce in the molds is also well known.

The object of my invention is to provide a method of. treating the molding-sand after having been used for one casting in such a manner that these globules or kernels are not formed, or if formed are eliminated, thus making it possible to produce molds having smooth inner faces and get castings having smooth surfaces.

To this end it consists in taking the sand after it comes from a mold and reducing the same to a fine condition either by crushing or grinding, this reduction occurring either before or after the tempering thereof, and then returning said sand when properly tempered to the molding-floor for reuse.

In the accompanying drawings I have shown an arrangement of a casting plant provided with means for carrying out my method, and in these drawings, Figure 1 isa plan view of the molding-floor and dumping-floor. Fig. 2 is a plan view of the upper floor of the foundry. Fig. 3 is a side elevation of the two floors. Fi 4 is an end elevation of a part of the apparatus. Fig. 5 is a section through one form of crushing or grinding apparatus, and Fig. 6 is a plan view of a modified form of crushing or grinding apparatus.

In the drawings, 1 indicates the molding and dumpingfloorsmpon which are placed the molding-machines 2, which receive the sand by means of spouts 3 from an overhead conveyer 4. After the molds are formed they are poured in any convenient place, and when the castings have set sufficiently the flasks are dumped in any convenient place, the sand retempered, screened, and returned to the molding-floor. Y In the plant shown in the drawings the molds will be dumped on a portion of the molding-floor, the sand passing down through openings 5 to a conveyer 6, by means of which it is moved toward the right in Figs. 1 and 3 until it reaches the spout 7, leading to the grinding or crushing apparatus. This grinding or crushing apparatus may be of various forms, that shown in Figs. 3 and 4 comprising two rollers 8 and 9, one larger than the other, upon which the sand falls, and by passing through the same it is reduced to a fine condition and all lumps therein are broken.

The rollers 8 and 9 may be driven by means of any suitable mechanism and. are located above the funnel or pan 10, from which a spout 11 leads to the horizontal conveyer 12. This conveyer may be of any preferred formsuch, for instance, as a screw conveyerand transfers the sand to a revolving screen 13, located over the hopper 14. The screen 13 removes all lumps, pieces of metal, and other hard substances which may be in the sand and the fine sand falls down into the hopper 14. The molded sand passes from the hopper 14 into the elevator 15, which deposits it in the overhead conveyer 4. The conveyers 4 and 6 may be of any preferred form, those shown in the drawings being of a type known as reciprocating conveyers, such as covered by the patent to Alfred M. Acklin, granted June 14, 1898, No. 605,621, and may be driven by any suitable gearing, the flights of the overhead conveyer being shown as driven by means of the crank 17 of suitable driving mechanism 18 and the flights of the lower conveyer being shown as driven from a crank 19 on the power mechanism 20. The particular gearing and other mechanism for driving the various conveyers and elevators, however, is wholly immaterial.

As shown in Fig. 2, there are two overhead conveyers 4 for supplying two lines of molding-machines. The elevator 15 deposits the sand in one of these conveyers and by means of a cross-conveyer 21 a portion of this sand is conveyed to the other overhead conveyer 4. This cross-conveyer is shown as driven from one of the longitudinal conveyers through the intervention of a bell-crank lever 22, but ohviously any other driving means might be employed.

The openings 5 in the foundry-floor are shown between the two lines of molding-machines, so that a single conveyer 6 serves to return the sand coming from the two lines of molding-machines.

Instead of the grinding or crushing rolls shown in Fig. 4 I may employ crushing apparatus such as shown in Fig. 6, the same comprising a pan 23, mounted so that it can rotate and having traveling upon the bottom thereof one or more crushing-wheels 25, which as the pan is rotated travel over the bottom thereof and crush the sand lying on said bottom. The pan may be rotated by any suitable mechanism-such, for instance, as from the shaft 26 and bevel-gears 27. A spout 28 conveys the sand to said pan and the scraper 29 scrapes the same off the pan into the hopper 30, leading to the conveyer 12.

Before being returned to the molding-machines the sand is tempered by having water suppliedthereto in sufficient quantities to give the sand the required degree of moisture to properly form in the molds. This water may besuppl-ied to the sand at any stage of its passage from the dumping-floor back to the molding-machines, and in the drawings it is shown as supplied after the sand has been rolled or crushed, and such water can conveniently be supplied by means of a waterpipe 32, projecting into the spout 11. The conveyer 12 and screen 13 will thoroughly agitate the sand and mix the same with the water.

By means of the crushing or rolling means shown the sand after being used in the molds is reduced to a fine condition, all lumps contained therein being broken and the grains thoroughly separated one from the other and all bond between said grains so thoroughly broken that when the water is added thereto there is no tendency for the grains to again adhere to form the kernels or globules which are so detrimental to the making of perfect molds.

It will' be understood, of course, that the arrangement of mechanism shown in the drawings has been selected for purposes of illustration only and that any arrangement of mechanism may be employed, and, furthermore, that any means for reducing the sand to a tine condition will serve equally as well as the grinding or crushing mechanisms shown.

What I claim as my invention, and desire to secure by Letters Patent, is-- 1. The method of treating molding-sand, which consists in taking the sand after having been used in a mold, reducing the same to a fine condition, tempering the same either before or after reducing, and then returning the same to the molds to be reused.

2. The method of treating molding-sand, which consists in taking the sand after having been used in a mold, grinding or crushing the same, tempering the same either before or after grinding, and then returning to the molds for reuse.

3. The method of sand-molding, which con.- sists in taking the sand after having been used in the mold, grinding or crushing the same, adding water thereto until properly tempered and then again forming into molds.

In testimony whereof I, the said WILLIAM J (PATTERSON, have hereunto set my hand.

WILLIAM J. PATTERSON.

Witnesses:

ROBERT C. TOTTEN,

F. W. WINTER. 

